Randomize blocks and trials but keep breaks in the same order

[Chloris]

Hi Jeremy,

I’m building an experiment with 3 blocks and 2 breaks (pauses). I’m wondering if there’s a way to only randomize the blocks and within-block trials but keep the breaks in the same order. That is, pause_1 should always appear after the first block regardless of which block it is (and pause_2 after the second block). I checked this thread but it didn’t mention breaks.

My current code only randomizes within-block trials:

Sequence("consent", randomize("block_1"), "pause_1", randomize("block_2"), "pause_2", randomize("block_3"), "send", "completion")

Thanks a lot!

Best,
Chloris

[Jeremy]

Hi Chloris,

Should pause_1 always appear after block_1 regardless of where block_1 ends up, or should it always appear after the first block to run, regardless of whether that’s block_1, block_2 or block_3? Assuming you mean the latter, you can achieve it like this:

var blocks = [randomize("block_1"),randomize("block_2"),randomize("block_3")];
fisherYates(blocks);

Sequence("consent", blocks[0], "pause_1", block[1], "pause_2", blocks[2], "send", "completion")

Jeremy

[Chloris]

Hi Jeremy,

I indeed meant the latter one. The code works perfectly. Thanks a lot!

Boyin

[ediachek]

Hi Jeremy,

I’m also trying to make an experiment with randomized blocks and this is super helpful! However, I have a few more questions.

My each block will include study trials and test trials. Right now, these are 2 separate templates and I’m not sure how to unite them into 1 block. Here is what I have so far, I’d really appreciate your guidance!

-Yev

//Phase 1 Block 1: Study Trials [randomized in Sequence]
Template("bell_bottoms_study_2AFC_1.csv", row =>
    newTrial("trials_study",
    
        newText("study_question","Click on the image as described in the audio")
            .center()
            .cssContainer({"margin-bottom":"1em"})
        ,
     
        //Load images
        newImage("target", row.target_filename),
        newImage("foil", row.foil_filename),
        
        //Load audio
        newAudio("audio", row.audio_file),
        
        //Display images
        newCanvas("image_study", 1000, 500)
            .add(0, "middle at 60%", getImage("target"))
            .add(550, "middle at 60%", getImage("foil") )
            .print()
            //.center()
            .log()
        ,
        
        //Play audio with instructions
        getAudio("audio")
            .play()
        ,
        
        //Allow to select
        newSelector("answer_study")
            .add(getImage("target"), getImage("foil"))
            .shuffle()
            .log()
            .wait()
        ,
        
        newTimer("post-trial", 1000).start().wait()
    )

//Phase 2: Test Trials [randomized in Sequence]
Template("bell_bottoms_test_2AFC.csv", row =>
    newTrial("trials_test",
    
        //Question
        newText("Which image did you see in the previous section of the study?").print().center().cssContainer({"margin-bottom":"1em"}),

        //Load images
        newImage("target", row.target_filename),
        newImage("distractor", row.distractor_filename),
    
        newSelector("answer_test"),
    
        //Display images
        newCanvas("image_study", 1000, 500)
            .add(0, "middle at 60%", getImage("target"))
            .add(500, "middle at 60%", getImage("distractor") )
            .print()
            //.center()
            .log()
        ,
        
        //Allow to select
        newSelector("answer_study")
            .add(getImage("target"), getImage("distractor"))
            .shuffle()
            .log()
            .wait()
    )

• This reply was modified 1 year, 2 months ago by ediachek.

[Jeremy]

Hi Yev,

If your first block consists of all the trials labeled “trials_study” and those named “trials_test” and you want them randomly (unevenly) shuffled, you could replace randomize("block_1") from the code above with randomize(anyOf("trials_study","trials_test")). If you’d rather have them evenly shuffled, use rshuffle("trials_study","trials_test")

Jeremy

[ediachek]

Hi Jeremy,

Thank you for your response and I’m sorry, I still have a question. Let me rephrase my issue.

Each one of my 4 blocks includes study trials and test trials. I would like the 4 blocks to be randomized across participants, and the trial order within each block to be randomized as well. However, test trials for block 1 should always follow study trials for block 1 because participants can only do a memory test on the items they have already studied. So possible orders of presentation would be:

[“study_trials_2″,”test_trials_2″,”study_trials_4″,”test_trials_4″,”study_trials_1″,”test_trials_1″,”study_trials_3″,”test_trials_3”]

OR

[“study_trials_1″,”test_trials_1″,”study_trials_3″,”test_trials_3″,”study_trials_4″,”test_trials_4″,”study_trials_2″,”test_trials_2”]

etc.

I was hoping to achieve this by just grouping study and test trials together into one variable “block” but not sure how to achieve that. I might also be missing another solution, so I would appreciate your advice!

Thanks again for all your help!

-Yev

[Jeremy]

In that case use two randomizes in seq, like this:

var blocks = [
  seq(randomize("trials_study"),randomize("trials_test")),
  // ...

Jeremy

[ediachek]

That woks great! Thank you!

[Author]

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